Shooting from the hip from when we had a couple. The 8dn's were the weight. don't recall the spring or rivets. The secondary, we would switch between the 47 degree with a silver or green spring and the apex mtn helix with the same springs. It is a split angle. It depended on snow conditions. Your jetting may be safe with the atacc. Send them a note, I'm sure they would be happy to help. I ride between the Tushars in Utah to the Big horns in Mt and everything in between. Currently pull the trigger at 10 k in Co.

It's been a few years but I had a great running Viper and this is what I have written down.
142.5 Mains
Clip in #2
55 pilots
21/42 gearing W 8 tooth 151"
I ran a 911 kit w 44 grams and stock weights.
Secondary was Hi tech E/R kit so can't help ya much there.
I also had the 3 filters in my airbox for more air.
To make this sled run you have to richen up the carbs by removing the vent tube from the airbox and let it hang down and vent to the underhood the way the SRX did. This will cause the carbs to go rich since the vacuum is removed from the float bowl.
So now when I tell you 142.5 mains, thats where I started. At 10k feet I ended up at 137.5s and it was a great running Viper.
Good luck.